AJP - Regulatory, Integrative and Comparative Physiology, Vol 252, Issue 1 109-R121, Copyright © 1987 by American Physiological Society
Factors from paraventricular nucleus mediating adrenocorticotropin release in cats
D. E. Carlson and D. S. Gann
Experiments were conducted in alpha-chloralose-urethan-anesthetized cats.
We stimulated the hypothalamic paraventricular nucleus (PVH) electrically
before and after intracerebroventricular (icv) injection of an antiserum to
arginine vasopressin (AVP), one to corticotropin-releasing factor (CRF), or
one to normal rabbit serum (NRS). Stimulation of the ventral portion of the
dorsal PVH led to increases in arterial pressure and heart rate that did
not change after any of the icv treatments. However, the effect of each
agent on the increases in plasma adrenocorticotropin (ACTH) after
stimulation was related to the area of the PVH that was stimulated. The
response to stimulation of a rostral area that extended dorsally from the
anterior PVH was blocked completely by the anti-AVP but not by anti-CRF or
NRS. The response to stimulation of a caudal area located in the dorsal PVH
was attenuated after anti-CRF, unchanged after anti-AVP, and augmented
after NRS. The antibodies that were given icv were found
immunocytochemically to enter the median eminence at sites that include
some adjacent to the portal vessels. Immunocytochemical localization of
AVP- and of CRF-containing neurons in the PVH showed that the anterior PVH
had the highest proportion of AVP neurons in the PVH but had only a few CRF
neurons. In contrast, the dorsal PVH contained the highest density of CRF
neurons in the PVH as well as some AVP neurons. We suggest that, in the
cat, the primary releasing factor for the anterior PVH is AVP and that for
the dorsal PVH is CRF.
